Project(Extend(Extend(AggregationJoin(Aggregation(??agg1: ?s, SAMPLE,
                                                  {},
                                                  G1=Group((?s),
                                                     BGP( ?s ?p ?o))),
                                      Aggregation(??agg2: avg(?o) , MAX,
                                                  {}, G1)),
                      ?s,
                      ??agg1),
               ?maxAvg,
               ??agg2),
        {?s, ?maxAvg})